A control device of a vehicle drive device including an engine, an electric motor, and a hydraulic power transmission device is conventionally known. For example, this corresponds to a control device of a vehicle drive device described in Patent Document 1. According to Patent Document 1, the hydraulic power transmission device is a torque converter and includes a pump impeller to which power from an engine is input, a turbine impeller outputting power to drive wheels, and a stator impeller rotatably disposed between the pump impeller and the turbine impeller. The electric motor is coupled to the stator impeller. The control device of Patent Document 1 drives the electric motor to change the capacity (capacitive coefficient) of the torque converter.